vars_pull {tidyselect} | R Documentation |
Select variable
Description
This function powers dplyr::pull()
and various functions of the
tidyr package. It is similar to vars_select()
but returns only
one column name and has slightly different semantics: it allows
negative numbers to select columns from the end.
Usage
vars_pull(
vars,
var = -1,
error_call = caller_env(),
error_arg = caller_arg(var)
)
Arguments
vars |
A character vector of existing column names. |
var |
A variable specified as:
The default returns the last column (on the assumption that's the column you've created most recently). This argument is taken by expression and supports quasiquotation (you can unquote column names and column locations). |
error_call |
The execution environment of a currently
running function, e.g. |
error_arg |
An argument name as a string. This argument will be mentioned in error messages as the input that is at the origin of a problem. |
Value
The selected column name as an unnamed string.
See Also
Examples
# It takes its argument by expression:
vars_pull(letters, c)
# Negative numbers select from the end:
vars_pull(letters, -3)
# You can unquote variables:
var <- 10
vars_pull(letters, !!var)